“Most of them will be overpriced,” [Warren] Buffett, chairman and chief executive officer of Berkshire Hathaway Inc., said… ”It’s extremely difficult to value social- networking-site companies… Some will be huge winners, which will make up for the rest.” Bloomberg BusinessWeek, 3/25/11

But that hasn’t stopped a parade of social-networking companies from preparing themselves to go public.

Renren Inc., China’s equivalent to Facebook, went public on May 4th. It’s the first social-networking site to do so.